Binary sensor from file

Configuration
1

Hi all,
thanks for great project as HA.
But I need a help, I searched forum and examples for whole day and tried many configs but no success.
I’ve got a json file containing:

{"tariff":"low"} or {"tariff":"high"}
changed with current energy tariff.
In configuration.yaml I have:

sensor:
 - platform: file
   file_path: /run/tariff.json
   name: Energy tariff
   value_template: '{{ value_json.tariff }}'

and automations.yaml:

- alias: ventilation on
  trigger:
   - platform: template
     value_template: "{{ is_state('sensor.tariff', 'low') }}"
  action:
   - service: fan.turn_on
     entity_id:
      - fan.intake_fan
      - fan.exhaust_fan

- alias: ventilation off
  trigger:
   - platform: state
     entity_id: sensor.tariff
     to: 'high'
  action:
   - service: fan.turn_off
     entity_id:
      - fan.intake_fan
      - fan.exhaust_fan

I want to turn on and off, but it doesn’t work. As you can see I tried both state and template. I think the problem is that the sensor is not binary_sensor.
How to make binary_sensor from file or from sensor?
Thanks
Jiri

2

First off, does your file sensor actually change state from high to low and vice versa?

Look in the developer tools states menu to check.

3

I don’t think so. Are you sure your sensor is sensor.tariff?
Can you see it it Developer → States?
My bet is you can not as it’s something like sensor.energy_tariff

4

Yes, this is it. Am I stupid, I searched everywhere but not the name. Thanks